Better error message when using pyd file as stubgen (python#8063)

TH3CHARLie · JukkaL · commit e05bd1c881b4 · 2019-12-03T15:34:42.000Z
Resolves python#8035.
diff --git a/mypy/build.py b/mypy/build.py
@@ -2004,9 +2004,11 @@ def parse_file(self) -> None:
                             self.path, os.strerror(ioerr.errno))],
                         module_with_blocker=self.id)
                 except (UnicodeDecodeError, DecodeError) as decodeerr:
-                    raise CompileError([
-                        "mypy: can't decode file '{}': {}".format(self.path, str(decodeerr))],
-                        module_with_blocker=self.id)
+                    if self.path.endswith('.pyd'):
+                        err = "mypy: stubgen does not support .pyd files: '{}'".format(self.path)
+                    else:
+                        err = "mypy: can't decode file '{}': {}".format(self.path, str(decodeerr))
+                    raise CompileError([err], module_with_blocker=self.id)
             else:
                 assert source is not None
                 self.source_hash = compute_hash(source)
diff --git a/test-data/unit/cmdline.test b/test-data/unit/cmdline.test
@@ -1458,3 +1458,11 @@ test.py:4: error: Missing type parameters for generic type "_PathLike"
 test.py:4: note: Subscripting classes that are not generic at runtime may require escaping, see https://mypy.readthedocs.io/en/latest/common_issues.html#not-generic-runtime
 test.py:5: error: Missing type parameters for generic type "Queue"
 test.py:5: note: Subscripting classes that are not generic at runtime may require escaping, see https://mypy.readthedocs.io/en/latest/common_issues.html#not-generic-runtime
+
+[case testErrorMessageWhenOpenPydFile]
+# cmd: mypy a.pyd
+[file a.pyd]
+# coding: uft-8
+[out]
+mypy: stubgen does not support .pyd files: 'a.pyd'
+== Return code: 2
